Measuring instrument



- 1944. v. CAPON MEASURING INSTRUMENT Filed May 1, 1943 Via-0E CAPo/v,

INVENTOR;

:ATTORN JEY.

Patented heels; 1944 1 My: -dnvent1om relates? mm m maasuringadnstmmenu?! made-has pamwlaw referenaetm w crometer r'whwh is wparticnlarlyadapted? i fimruge',

as a checking or dnspeetion"instmmentiatmamen-i' machine part liegwithin the specifled tolel ances,

tblrano rangm andi indicatingwhether r 'not thewmeasmted dimensibn lies:with 'lmsuoh range". Imis mstfll iunther-dbject of my inventmn ttvprovide 5 aszmeasuring deviee oiithe character sett'mes in lerg uantitiefiw is -fessentialwh t;

vidleaimeasuring dvice ofthe characterset anceswvtmsee'whetherf(Sr-not?thercorrespondmg Whenfthise operation 13+ perf6rmed=with;-con=ventional? mierbmetersr or; the, like measuring seamen; it is necessary"tit read? the v microm Qtrflnd'fi determihm the actual dimension of ttiepart3 mi-1s, must then" becomparedfw-itlr th mm in the pzecedingparagraphs which in eludes means ffin adju sting the initial setting ofv tunes ofi construetiom permitting the initial ad justments of theinstrument to-beareadi-ly 'mede specifiedfidimensien* townie part todetermine whether not "if; iens within the tolerances specified-2*Sifzch-anpperat1on-istime consum= curately:--readwitiflh'- elbse' li'rnits 'thvmeasui'- mentmmade'with:ordtnaryymierometer-r measur ingfdewces; Furthermore, frequenterrorsmceun aegiresuwofifthe "requirement"for eomparing the measuredwliz'nensimrwith: therspec'iflepi? dimenfi Ifitfewmeasuredr di mens imwith that specifiedmansibm tOE Dl'OWdE; wmeasuring! gievice of the character seti forth: in; them preceding:parmgrapm which" 1 companying drewing wliereinz m2: "1 isampers'peotiveView of? the preferred embodiment sof'imy ifiven tit bn';a? vertical? seetibnal P View through the instrumen llilstrated in'f'ig. :1; 3 1s--a'r1 perspecfiive'=-View illustrating in detail one oftliwtwo indexing meansa employed' the instrument we:

R'efmihgg to? tim drawing; L have illizstrated" the! preferredembddiixienflof mydnventiom as' 1 cent-re? Boss? 3* is provided with avver-fy finally extending bore 6*" which" is internally 1' tin-eadedaa jindieated -at-1-wima amiurmemw I The graduations l preferably include azero graduation I 2 and a series of graduations extendj ing in oppositedirections from the zero'gra'dua-' the dead-line post H,

tion l2, these latter graduation beingidentified by suitable indicia I3and classed by'the ences minus or plus, respectively. I

refer- For use with the English system of measurements the dial 9 ispreferably provided with a" total of twenty-five or fifty; graduationswhich,

with forty threads per inch for the micrometer thread 1,-makeeachgraduation correspond, respectively, to 0.001 inch or 0.0005 inchvertical movement of the boss member Sand dial 9.

I From the upper surface of the' dial!) rises a sleeve M which isthreaded externallyto receive a lower knurled clampingring i5 and anupper outer chuck member l6. r The uppermost portion of the sleeve I4 istaperedas indicated at I] in Fig. 2 andsplitlongitudinally as shown atH3 in Fig. .1 todefine a plurality'of spring chuck members IS. Thetapered surface I1 coacts with a similar tapered surface 29 provided onthe interior of the outer chuck:member |6.- By this mean rotation of,the outer chuck member 16 may be effective in moving the spring'fingersminwardly to clamp and secure a'measuring rod 2| which is passeddownwardly through an'interior bore 22 extended vertically throughtheboss 8 andthe sleeve I4. t t

The measuring or gauging rod 2| may be of any desired length, but it ispreferably provided on,

its lower end with a removable hardened and polished tip 23 adapted toresist wear and} prevent changing of the calibration of the instrumentonce it is set. If desired, the uppervend'of the rod 2| may be formed asa male element adapted toconnect to the opposite end ofa .similar rod inplace of the tip 23 whereby a numberof relatively short length rods 2|may be-interconnected deep. To adjust the instrument, the dial 9 isturned to the position illustrated in Fig. 1, placing the zerograduation opposite the dead-line post H. The chuck I.6l9 is loosenedand the rod 2! is shifted to a positionsuch that the lowermost point ofthe tip 23 isprecisely 2.000 inches from the under gauging surface'2,this dimension being determined by the use'of gauge blocks-orstandardized micrometers or like measuringinstruments. When so adjustedthe rod 2l= is locked in positionby rotating theouter chuck member It.This may be preliminarly accomplished .by grasping the knurledouterperiphery of the member [6 with the fingers. For final securing, itis preferred to use a spanner wrench and for this purpose suitablespanner holes 24 are provided in the member l6.

In checking the depth of the hole in the workpiece, the instrument isplaced with the rod 2| extending into the hole. The dial 9 is thenturned as by grasping the outer periphery thereof with the fingers, thesame being knurled as shown at 25 to facilitate thi operation. The dial9is turned to a position such thatthejtipf23 is just touching the bottomof the bore to be checked, this condition being readily detected by thefeel of the dial. If the hole is precisely 2.000 inches deep, the" zerograduation l2 will be disposed opposite If, on the other hand,

the depth is 2.002 inches, the graduation indicating plus 0.002 inchwill be opposite the dead-line post I l,-clearly indicating that thehole being checked is 0.002 inch deeper than specified. Because oftheimpossibility andthev lack of necessity of making machine-partsprecisely to a specified dimension, it -is;thecommon practice tospecific tolerances as, for example, H

2 inche s'i0005 in ch!" 4 z To determine whether or not the indicateddifference; between the specified dimension and the measured dimensionfalls within the specified 26 and 21 which may be set with respect tothe dial 9 to positionsrepresenting the tolerance lim its. Themembers26and2l are identical except that one is made right handed andtheother is made left-handed. The preferred form'of con} struction is shownin Fig. 3. Each ofthe members 26 and 2'l'is preferably formed ofthinmetal and includes, a central washer-like portion 28 which isboredas indicated at 29 to receive the sleeeve portion 1., Anoutwardlyprojecting arm portion 30 is tapered to define an indicating point GIand a, laterally extending ear or lugbent up at right angles tothe planeof the arm 30 as indicated at 32 toprovide a portion which maybe readilyfelt by the fingers, thus permitting the position of the arms 26 or 21relative to the deadline post H to be detected by feel by a blind personand also to serve as finger-pieces or han; dles to facilitate theinitial setting of the posi tion of the members 26 and21. l

To set the position of these members .the

knurled clamping ring I5 is loosened and the.

members 26 and 2! are. turned to positions with respect to the dial 9indicating the specified plus and minus. tolerances for the dimensionto'jbe checked. The fingers may then be clampedin their adjustedposition byproperly rotating the clamping nut l5, spanner holes-33 beingprovided to permitthefingerstobeso securely looked as to preventinadvertent displacement of the members during the use of theinstrument.

While-.1 have described the adjustment andoperation of theinstrument-in-= connection with gauging the depth of a bored hole, itwillbe obvious to those skilled'in. the art that the arms 4 and 5 may begiven any desired special con figuration adapted tosuit'a particularmeasuring job-or, alternatively, that auxiliary deviceslsuch cular bore31. transversely of the slotted arm 5 of the base and may be tightenedto spring the metal of the base inwardly about the threaded boss 8 totake.

upfor any lost motion While the friction of 'the 2,sc4,127 l as gaugeblocks or jigsmay be employed permit the device to be used formeasuringexternal dimensions suchas lengths or breadths of machineparts.

from the specified dimension may beeasily'ascerrelation with oneoftheside walls of the slot as indicated in Fig. 4.

tained and means are provided for indicating 1 whether or not themeasured dimension falls within the specified tolerances of the stateddimension. The indexing means employed are so arranged as to permit thedevice to be readily used by aperson; who has impaired eye sightor,

who is blind. y

The base member I ispreferably made of substantial weight anddimensionsto lend ample rigidityto the base so that the gauging surface 2 maybemachined or ground with high accu racy. Sufficient weight may thus alsobe incorporated to facilitatedetermining byfeel the setting at which thetip 23 engages the bottom of the hole or the surface of the workpiece.

, Preferably the dial 9 is made at least two inches in. diameter so thatthe graduations 10 maybe spaced apart an adequate distance to permitdirect reading of the instrument while the instrumentisin place inchecking position and by persons of relatively impaired eye sightwithout While I have shown and describedthe pre i ferred embodiment ofmy. invention, I do not desire to be limited to anyof the details ofconstruction shown or described herein, except as de'- finedin theappended claims. i 1

.Iclaim: I 1. ,In a measuring instrument, thecombination of: abasememberdefining a reference surface; 1 ameasuring member defining a measuringpoint; means mounting said measuring member on said base member foradjustable movement relative thereto,'whereby the distance of saidmeasuring point from saidreference surface may be ad justedto apredetermined dimension; micromgroove; and a stop member on said basemember requiring the use of auxiliary magnifying lenses.

When the instrument has been set to measure or check the desireddimension; the dial should. not be capable of rotation through more thana single revolution as otherwise the coincidence of the zerograduationwith the dead-line post .H

would actually dispose the tip .23 at aposition which would be in errorby one-fortieth of an 3 inch for eachrevolution the dial has made. To

prevent such inadvertent error, I prevent the ro tation of the dialthrough more than a single revolution by providing an annular groove Wonthe boss 8 into Which projects a stopscrew 34, the inner end 35 of whichhas a diameter less than the width of the groove by an amount which willpermit a little less than a complete rotation of the dial in eitherdirection.

, In order to take up for any looseness which may occur betweenthe base2 and the threaded boss has may occur by reason of wear between theseparts, I. prefer to form the base with a longitudinal slot 36 extendingfrom the threaded bore 6 and terminating at its outer end in a air- Acompression screw 38 extends boss in the base may be accurately adjustedby means of a set screw 39 extending into abutting eter meansinter-engaging said base memberand said: measuring member formovin saidmeasuring member relative to said base member, said micrometer meanscomprisinga boss threadedly 1 engaged with said base member and havingan indicating dial secured thereto for indicating the differencebetweenthe distance of said measure ing point from said reference surface andsaid said boss having predetermined dimension, formed therein acircumferentially extending received in said groove and having a widthless than the width of said groove by an amount sufficient to limitmovement of said dial to less than one revolution.

2; In a measuring instrument, the combination of: a base member defininga reference surface i and having a threaded bore extended there fromsaid reference surface may be adjusted to i a predetermined dimensionatany selected position of said micrometer, said micrometer means throughnormal to said surface; a measuring member defining a measuring pointmicrometer means inter-engaging said base member and said measuringmember for moving said measuring member relative to saidbase member;means mounting said measuring member on said mi-j. crometer foradjustable movement relative thereto, whereby the distance of saidmeasuring point comprising a threadedfboss engaged with the threadedbore of said base member and having an indicatin dialsecured thereto forindicating the difference between the distance of said measuring pointfrom said reference surface and said predetermined dimension, said basemember having a slot cut therein parallel to said bore and extendingradially outward therefrom to divide said base member into twointegrally formed parts; and an adjusting screw extended across saidslot and threaded into one of said parts for drawing said parts towardeach other to adjust 6 the threaded engagement between said base memberand said boss to compensate for wear l in said threaded engagement. lVICTOR CAPON.

